Telephone-exchange system.



W. AITKBN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 25, 1913.'

Patented Nov. 18, 1913.

3 BHEBTS-SHEET 1.

H mm @5 $193531 TOR flTTO/P/VEYS W. AITKEN.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED JUNE 25, 1013.

1,079,1 56. Patented Nov. 18, 1913.

3 SHEETS-SHEET 2.

W. AITKEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNIIZS, 1013.

1,079,156. Patented Nov. 18, 1913.

3 SHEETS-SHEET 3.

flTTORW/EKS,

UNITED STATES PATENT orrioa.

WILLIAM AITKEN, 0F LIIZERPOOL, ENGLAND.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Nov. 18, 1913.

Application filed June 25, 1913. Serial No. 775,706.

To all whom it may-concern:

Be it known that I, WILLIAM Arman, residing at Liverpool, England, haveinvented certaln new, and useful Improvements in Telephone-ExchangeSystems, of which the following is a specification.

My invention relates to telephone exchange systems and more particularlyto an improved method of registering calls According to my inventionthere is provided in a telephone system, a substation meter which can beset so as to automatically limit the number of calls, which can be "ingrespectively. These methods involve a great amount of book-keeping andaccounting by a large clerical stafl', rendering of accounts, forwardingreceipts for inoneys paid and the provision of a staff for read ingmeters and for like purposes.

In the preferred method of carrying out my invention, it is proposed tomake the part ofthe meter which is set a removable unit or art of ifremovable unit as referred to a ove, and that these units should be madein a sealed form and sold at any telephone ofiice or otherhsuitableplace. A party then desiring a telephone line would pay preferably aninstalling charge and purchasea registering unit capable of registeringsuch a. number of calls as is convenient accordin to his requirements.When the unit is ex austed it would bereplaced by 'a fresh one or eachsubscriber might have tiivo units, one to replace the other, the one notin use being taken toa telephone ofiice and re-set fora fixed charge.The changing or fixing of'the units would be done in conjunction with anofficer at the exchange to prevent fraud, preferably in a manner to bedescribed.

My invention will be more fully understood from the followingdescription taken in connectionwith the accompanying drawings, in whichFigure 1 illustrates, partly diagrammatically, a subscribers instrumentand meter. Fig. 2 shown on an enlarged scale and in dctail the switchhook and a meter locking de vice. Figs. 3 and 4 illustrate means forgiving a warning when a unit is nearlv exhausted. Fig. 5 shows theessential parts" of the cord circuit at the exchange and all the linesrunning to a called substation with the battery reversing arrangementsfor automatic and manual exchange working, and Fig. 6 is a similardiagram to Fig. 5, the meter, however, being operated bydifferences inpotential in a manual system.

Referring to Figs. 1 and 2 the substation comprises the usual receiver1,'transmitter 2, switch-hook 3, ringer 4: and condenser 5. Thesubstation A also comprises a meter M. The general construction of themeter M is of a well-known type and comprises a core 6with an armature7. The armature 7 has attached to it a pawl 8 which is adapted to engagethe teeth of a ratchet wheel 9. This ratchet wheel is revented fromreverse rotation by a paw 10. A spring 11 is connected at one end to thepawl 8 and at, the other end to a fixed part 12, and keeps the pawl 8 inengagement with the ratchet wheel 9. A pin 13 prevents the pawl 8dropping too far. Mounted on the spindle of the ratchet wheel 9 are thenumber disks 14: of the counting device. The core 6 is provided with twowindings as shown, one winding 15 being of a large number of turns andconnected with the rods or terminals -16. The other winding 17 consistsof a small number of turns and is connected at one end to one of theterminals 16 as shown and at the other end to contact 18. A spring 19 isconnected to the lower of the two rods 16 as shown in the drawings andthe-arrangement is such that on the armature 7 full amount ofcurrent topass to the micro- To the armature7 is attached an extensibn' 21 havingpivoted to it a hinged barbed en gaging arm 22. This arm 22 on theattraction of the armature 7 slips under the extension 23 (see Fig. 2)of the switch-hook 3 after the receiver is removed from the hook andholds it so as to prevent flickingofv the receiver hookat the calledstation from causing-registration on the meter. The plate 24 is thefront plate of the casing in which the meter is arranged and an openingis left so that the portion of the meter inclosed Withinthe casing 25and the front plate 2-1 can be removed. The casing of the meter isprovided at the back witha door 79, which is hinged at the bottom asshowmand has a lock with seal over at its upper end whereby access maybe had to the interior of the casing. The door also contains a holethrough which the pawl 9 passes. The removable part ofthe metertherefore, consists chiefly;- of the" number whe'elslt-and the ratchetWheel 9, the part 12 to which spring 11 is attached, being attached tothe nonremovable part. A window 26 fitted in the back of the casing isprovidedinfront of the number disks'so that these can be read.

The front plate of the removable portion of the meter is provided at itsfour corners with pins. In Fig. 1, two of these are shown namely the pin27 and the pin 28. Two other pins 29 and 30 similar to 27 ar provided atthe other corners of thewremovable part. These pins are indicated inFig. 3 and their purpose will hereinafter be fully described as alsothat of the pin 28. Beneath the meter is arranged a locking magnet 31,consisting of a core having a winding 32 connected atone end to earth asshown and at the other end to a spring 33. Adjacent to the spring 33 aretwo springs 34 and 35. The locking magnet 31' is provided with anarmature 36 pivoted at 37. and having an upward extension 38 which isadapted to engage the spring 34;. When the armature is attracted a pin39 on the extension 38 .is

ed to engage the-pin 53 as described in conadapted to engage the plate40 to limit the upward extent of the movement of the,extension 38. 1 I

Where the meter is operated by reversal of current in the line apermanent magnet 41 is provided which polarizes the core 6.

Means are provided for indicating to the subscriber and preferably tothe operator the fact that no further calls can be made from theexchange owing to the meter having registered the number paid for andpreferably also a signal should be given to the subscriber when themotor has registered a number of calls approaching the 'inaxinuunnumber. 1

-Were not employed.

In Fig.3 there is diagrammatically indicated a method of giving thesignals just referred to, and in this figure there is also illustratedthe use of the pins 27, 29 and 30 already referred to. The side of theline a is connected to the meter M, and through the pin 27 to the spring52. The other side of the line b is connected through the microphone 2,receiver 1 tothe pin 29 which is connected to a spring 53 and to aspring 54:. I i

The pin 30 connects springs 55 and 56 to a buzzer 57. The number Wheel14, shown'in Fig. 3, carries a pin 58. W'hen the "pin reaches a positionwhere it engages the s ring 54 it closes this spring on to spring 55,thereby closing a circuit from the 5 side of the line, through thebuzzer, thus giving an indication that the calls paid for are nearlyexhausted. .On further rotation of the numeral wheel 14 the pin 58engages the spring 53, moving this out of contact with the spring 52 andthereby opening the circuit of the line and preventing any further callsbeing made until the meter is re-set or a new unit substituted therefor.

In Fig. 4, the arrangement just described is shown in more elaboration.59, 60, 61 and 62 are number wheels similar to the number wheels 14already described. Contact pins 63 of insulating material are providedon each of these wheels and'these contact pins are adapted to force intocontact four pairs of springs 64, 65, 66 and 67. The pins 63 may be soarranged that contacts are made between the respective pairs of springs64, 65, 66 and 67when the meter indicates a number, for example, 9999fThese springs are connected together as shown so that on the meterregistering 9999, a circuit will be closed from the 1) line through thebuzzer 57. The pairs of springs 64', 65,. 66 and 67 are placed withinthe incased removable portion of the meter and areconnected by suitablewires passing out of the casing to the pins 27, 29 and 30,'but forconvenience in Fig. 1 the connections to these pins are not shown, butthe circuits are shown as if these pins An additional wheel 68 may beprovided carrying a pin 58 adaptnection with Fig. 3 to" open the circuitof the line while at the same time making contact with spring 56 andthereby closing a to check the additional registering for a trunk linecall. The meter for the latter purpose should-preferably be of a typethat returns automatically to normal after being disconnected from thecircuit so that after the operator has asked the caller to move theswitch hook as many times as there are pence in the fee to be charged,she throws the-meter 81 into circuit, when it would check the amountof.the fee, the calling meter, however, only adding this number to theprevious total. The plugs of the cord circuit are indicated by dottedlines 82 and 83 being the tips, and 84 and 85 being the rings. The otherdetails will .bec'onsidered when describing the circuit.

In Fig. 6 a cord circuit is shown divided.

by a repeater instead of by condensers as in Fig. 5. The tipsiof theplugs are indicated by dotted lines at 120 and 121, the rings beingindicated by dotted lines at 122 and 123,

the sleeves or test-circuit being indicated at 124 and 125. The commonbattery is shown at B. Other details of the circuit will be describedwith the operating.

The operating of the system and the circuits are as follows: In anautomatic system the calling dial indicated at 86 in Fig. 1 is providedwith springs to short-circuit the meter if necessary, but as the callincurrent is not in the direction to operate t 1e meter this will notusually be necessary unless to reduce the resistance of the circuit. Thereceiver '1 will be lifted and the dial moved in the well-known manner.The circuit completed on lifting the receiver is from central battery B,lower winding of relay 87, contact 88,-contact 89, line .b, transmitter2, receiver '1, switch hook springs 91 and 90, springs 34:

and 35, winding 15 line a, contacts 92 and 93, contacts 94 and 95, upperwinding of relay 87, back to battery. The automatic func tions, thattake place do notform part of my invention and the line is extendedthrough to the called station. When the receiver 96 is lifted a circuitis completed from central battery '13 lower winding of relay 97,

microphone 98, substation A, receiver 96,"

switchfhooksprings99 and 100, upper winding of relay 97 to other side ofbattery B.

Relay 97 is energized andeompletes a circuit from earth, winding ofrelay 101,,contacts 102 and 103 of relay 97 to battery B. Relay 1.01 isenergized and reverses the connections of battery B to the aand 6 wires,the circuit ,being from battery B, through lower winding of relay 87contacts 101 and 94 of relay 101 to the a side of the line and then backover the 1) side of the line through contacts 89 and 105, upper windingof relay 87 to battery. The direction of current in the meter winding 15is now of such a character as to strengthenthe magnetism induced in thecore by the ermanent magnet 41, and the armature 7 is attracted to thecore end. ,The receiver .1 is oil' the switch hook and when the pivotedbarbed arm 22 strikes against the extension 23 of the switch hook it isdeflected under it and the spring acting on the arm 22 causes the barbedhead to engage with 23 so that the armature 7 cannot fall away when thewinding 15 is short-circuited by winding 17 on the closure of thecontacts 18 and 19 or when the battery is reversed by the calledreceiver being replaced. \Vhen the armature 7 is first attracted, it, bymeans of the pawl 8, causes the meter to register one call in awellknown manner. \Vhen the receiver is re placed the extension 23 islifted and the armature 7 with the upright 21 and barbed arm 22 are freeto fall away when the circuit is opened at the springs 90 and 91 of theswitch hook. The condenser 20 is only required when winding 17 is usedas a parallel circuit to the winding 15.

TV hen the arrangement shown in Fig. 5

-is used on a switchboard which is manually local call, as for longjunction'and trunk line connections. The call would be received on or beextended to an operators position, where the toll lines could beconnected. The operator after making the desired connection would insertthe meter 81 by means of the key 80 the circuit then being from batteryB by lower windingof relay 87, contacts 101 and 94, winding of meter 81,contacts 106 and 92 to wire A. The meter 81 may either record the totalvalue of the calls made or preferably only the value of the call aboutto be made and returnto zero when disconnected from the circuit. Theoperator asks the caller to move the switch hook a number of timescorresponch ing to the scale of charges and she would check this by thereading on the meter. The

repeater winding 144 to the other *side of the battery. The checking isas before de- 6 are very similar to those shown and-described inconnection with Fig. 5.

When-two lines have been connected together as described in connectionwith Figs. 1 and 6 the supervisory relays 126 and 127 are energized andthe lamps 128 and 129 are shunted out by the resistances 130 and 131which are brought into circuitby contacts 132 and 133, and 134'and 135respectively. The lamp circuits are completed from battery B,resistances 136 and 137, lamps 128 and 129, sleeves of plugs 124 and125, Winding of cut-ofl' relays 138 and 139 to earth respectively. Whenthe operator desires to register a call she brings the meter 140 intocircuit by ressing key 141. This completes a circuit rom battery Bthrough battery B, meter 140, contacts 142 and 143 of key 141 to lineI), through the instrument shown in Fig. 1 andback to the a line,

scribed, but the meter at the calling station A has no permanent magnet41 and the meter is biased against the normal current from the batteryB. As, however, this bat tery is now reinforced by battery B the metersare energized that at the calling station recording the increased total,and the operators meter indicating the value of the present callcorresponding to the number of times the operator presses the key. 'Inthis case'the subscriber really checks the registering by the operator.The operators telephone and the,key for connecting it to the line areshown at 145 but form nopart of my invention. I

The subscriber utilizes the last number on the unit for obtaining theassistance of an oflicial at theexchange to replace the exhausted unitby a fresh one. The rold unit will be withdrawn and at the same timecurrent at a suitable voltage'will be supplied to the 6 wire by theexchange ofiicial, the circuit being from the 6 wire, contacts 34 and ofrelay 3,1, 'inding 32 to earth.

Relay 31 is energized andarmature 36 attracted to the core end. Pin 38is carried through the hole in the channel formed by the plate 40 andlifts sprih'g 34, the small projection39 on the pin 38 preventing thelatter from'being raised sufiiciently to allow the spring 34 to breakcontact with the spring 33. The tip of the spring 34 is however liftedsufliciently to allow of the pin 28 of the new unit, which pin is of aninsur lated beveled type engagingwith-the inside of pin 34 to cause itto break with contact 33 and make contact with spring 35. Should the oldunit be withdrawn and the exchange be not advised, the spring 34 wouldfallinto the. channel formed; by the pl'ate 40 and the pin 28 ofa newunit inserted would pass over the tip of the spring 34 and the linecircuit would remain open at springs 34 and 35.

Though it is preferred to provide areplaceable unit as described,-thisneed not be -provided as other methods of setting the meter might beemployed.

It is obvious that various other modifications might be made in themethods of carrying this invention into efi'ect, those specifitalkingcircuit, a call register adapted to register a predetermined number ofcalls,

and means controlled by said register for rendering said talking circuitinoperative when all of said predetermined number of calls have beenregistered.

3. In a telephone system, a line, a call register adapted to register apredetermined number of calls, an electrically-operated sig- .nal, meansfor operating said signal a short time before all of said calls areregistered,

and automatic means controlled by said register for rendering said lineinoperative when all of said calls are registered.

4. In a telephone system, a subscribers talking circuit, a call registercomprising an electromagnet and a readily removable registering unitcontrolled by said electromagnet, said unit being adapted to registeronly a predetermined number of calls, and means whereby when said unitis removed said talking circuit is rendered inoperative.

5. In a telephone system, a subscribers talking circuit, a call registercomprising an electromagnet and a removable registering unit controlledby said magnet,- said unit being adapted to register only apredetermined number of calls, means for rendermg said talking circuitinoperative when all of said calls havenbeen registered, and means forrendering the talking circuit inoperative when said unit is removed.

6. In a telephone system, a subscriberis line, a call register includinga removable registering unit, said unit being adapted to register only apredetermined number of calls, and means for preventing said unit frombeingreplaced after it has been removed. I

7 In a telephone system, a subscribers line, a call register including aremovable registering unit, said unit being adapted to register only apredetermined number of.

calls, an electromagnet connected with said last-mentioned electromagnetfor preventing the unit, after it has been removed, from being replaceduntil said last-mentioned electromagnet has been energized.

8. In a telephone system, a subscribers talking circuit, a call registerincluding an electromagnet and a registering unit controlled thereby andremovable from the telephone system independently of the electromagnet,said unit being adapted to register only a predetermined number ofcalls, a subscribers talking circuit partly carried by the removableunit, part of the unit being connected to the remaining part of the cir-15 cuit by separable terminals, whereby when the unit is removed saidtalking circuit will be broken.

In testimony whereof I have afiixed my signature in presence of twowitnesses.

, WILLIAM AITKEN.

Witnesses:

- WALTER'H. DERRIMAN,

ALBERT JONES.

